Method and apparatus for gas induced mixing and blending

Abstract

The invention relates to a mixing and blending system in which pulsed air or gas bubbles (45,46,47) of predetermined variable size and frequency are injected into a tank (10,60,80) containing materials to be agitated or stirred for mixing and blending. The air introduced at the bottom of the tank through an air inlet opening (24, 25). There may be more than one air inlet and the inlets may be provided with accumulator plates (42) depending upon diameter and height of the tank in which the mixing and blending is taking place. The inlets are located so as to create circular toroidal flow (48, 50, 52, 54) of fluid in a generally vertical plane. The accumulator plate has the purpose of assisting the formation of essentially a single bubble (46) from the compressed air charge made to the air inlet and increasing the time required for the bubble to rise through the liquid by causing it to be formed more quickly and closer to the bottom of the tank. Hence, the accumulator plate (42) is utilized in low viscosity liquids such as water.

I claim: 
     
       1. A method for air or relatively high pressure induced blending and mixing of liquids and other materials in a container having side and bottom walls, comprising: (a) locating first compressed air inlet means in close proximity to the bottom of said container at a predetermined location,   (b) introducing compressed air or relatively high pressure in predetermined pulsed quantity and frequency to said container through said air inlet opening, each said pulsed quantity of air being introduced to said container at approximately the same point in time the previous pulsed quantity reaches the surface of the materials in said container,   (c) forming an air bubble from each pulsed quantity of air introduced through said air inlet opening so that substantially discrete, single bubbles of spherical segment shape are formed, and   (d) creating generally circular, vertical toroidal flow patterns within said material such that said material moves upwardly with said bubble and then outwardly in proximity to the surface and then moves downwardly toward the bottom in a continuing, controlled flow pattern for mixing and blending the materials in said container.   
     
     
       2. The method for blending and mixing according to claim 1 and further including locating said at least one air inlet means at the center of said container. 
     
     
       3. The method for blending and mixing according to claim 2 and further disposing a plurality of second compressed air inlet means on a concentric line with respect to said first inlet means, said second compressed air inlet means being of a predetermined number and generally equispaced and further being pulsed with air generally simultaneously and separately after a bubble from said first means. 
     
     
       4. The method for blending and mixing according to claim 3 and further including disposing said concentric line of second inlet means approximately midway between said first inlet means and the side wall of said container. 
     
     
       5. The method for blending and mixing according to claim 4 and further including disposing a plurality of third compressed air inlet means outwardly of and on a concentric line in respect of said first and secod inlet means, said third air inlet means being predetermined in number and generally equispaced and further being pulsed with air substantially simultaneously and separately after pulses to said first and second means. 
     
     
       6. The method of blending and mixing according to claim 1 and further including disposing a flat accumulator plate means generally horizontally and slightly above each said air inlet means such that air from each said air inlet opening is introduced to said container on the underside of said plate so that a bubble from a pulsed quantity of air is formed in close proximity to the bottom of said container. 
     
     
       7. A method for air induced blending and mixing of liquids and other materials in a container having side and bottom walls, comprising: (a) locating first compressed air inlet means in close proximity to the bottom of said container at the center thereof,   (b) introducing compressed air in predetermined pulsed quantity of from a minimum volume of about 1 cubic inch into said container through said air inlet opening, each said pulsed quantity of air being injected into said container in less than a second at approximately a frequency determined by the same moment in time the previous pulsed quantity reaches the surface of the materials in said container,   (c) forming an air bubble from each pulsed quantity of air introduced through said air inlet opening such that substantially discrete, single bubbles of spherical segment shape are formed, and   (d) creating generally circular, vertical toroidal flow patterns within said material such that said material moves generally upwardly with said bubble and then outwardly in proximity to the surface and then moves downwardly toward the bottom in a continuing, controlled flow pattern for mixing and blending the materials in said container.   
     
     
       8. The method for blending and mixing according to claim 7, and further disposing a plurality of second compressed air inlet means on a concentric line with respect to said first inlet means, said second compressed air inlet means being of a predetermined number and generally equispaced and further being pulsed with air generally simultaneously and separately after a bubble from said first means. 
     
     
       9. The method for blending and mixing according to claim 8 and further including disposing said concentric line of second inlet means approximately midway between said first inlet means and the side wall of said container. 
     
     
       10. The method for blending and mixing according to claim 9 and further including disposing a plurality of third compressed air inlet means outwardly of and on a concentric line in respect of said first and second inlet means, said third air inlet means being predetermined in number and generally equispaced and further being pulsed with air substantially simultaneously and separately after pulses to said first and second means. 
     
     
       11. The method of blending and mixing according to claim 7 and further including disposing a substantially flat accumulator plate means generally horizontally and slightly above each said air inlet means such that air from each said air inlet opening is introduced to said container on the underside of said plate so that a bubble from a pulsed quantity of air is formed in close proximity to the bottom of said container. 
     
     
       12. Apparatus for air induced blending and mixing of liquids and other materials in a container having side and bottom walls, comprising: (a) at least one air inlet opening in close proximity to the bottom of said container and having a predetermined location therein;   (b) an accumulator plate means generally centered over and horizontally disposed with respect to said at least one air inlet opening so that air is introduced into said container from said at least one inlet opening on the underside of said accumultor plate means, said air being injected into said container from said opening is then directed outwardly toward the periphery of said plate and upwardly around the peripheral edges thereof to effectuate the formulation of a substantially single, discrete air bubble around said plate and which bubble releases from said plate and rises in said fluid medium to induce blending and mixing currents therein; and   (c) control means for said air inlet opening including a supply of compressed air connected to said air inlet opening and also valve means for controlling the pulsed introduction of compressed air to said air inlet opening.   
     
     
       13. The apparatus according to claim 12 and wherein said accumulator plate means is generally round having a diameter from about 1/10 to 1/20 of said container. 
     
     
       14. The apparatus according to claim 13 and in which said accumulator plate means has a diameter of about 1/16 the diameter of said container.